Response to the Letter to Editor

Evaluating the Impact of Diagnostic Platform Variability on Immunoassay Results for Vitamins B12 and D". 1 In your letter, you have rightly brought out the limitations of tailor-made PT samples for harmonization studies. 2 You have also rightly pointed out their limitations regarding the preanalytical variations, which constitute the major component of laboratory errors.More effectiveness and robustness of patient samples compared to the PT samples in assessing the analytical assessment range and thence their clinically reportable ranges, hook effect, and prozone phenomenon have been rightly underscored in this letter.These are all particularly linked to the validity and integrity of any immunoassay.Therefore, your recommendation to substitute the PT samples with patient samples definitely shows a better alternative for assessing the effectiveness of an immunoassay procedure that can provide a more robust SOP for that procedure as well as ensuring integrity in reporting across different analyzers.However, the authors of the above-mentioned article have also expressed their valuable opinion about the identification of numerous discrepancies in assessing the vitamin B12 and vitamin D levels by immunoassay techniques on different analyzers, and reiterated that their interpretation should be made cautiously across different platforms of immunoassay.They have also suggested the need for further standardization of the procedure, and your suggestion and gap analysis in this letter will definitely help to breach some limitations of the concerned study and bring up more consolidated and integrated results of similar studies in future.